Avenge or Die
by SherlockWasHere
Summary: Fiona Mae Dagger is one of SHIELD's best agents. When an incident in London leads to her working with the worlds only consulting detective, she and Sherlock, along with the Avengers, must race against the clock to stop Loki once and for all
1. Chapter 1

**Ch.1**

Fiona walked purposefully down the street, dragging her luggage and desperate to get out of the rain. It wasn't exactly the perfect first day in London. She had always pictured that a vacation to London would be bright and cheery, the exact opposite of her visit so far. The people were, in general, quite rude to her, she already missed her job, and the rain didn't help one bit. She never got time off from work, and now she knew why. Civilian life was incredibly dull, but she had been granted vacation. It wasn't really a vacation, but more of a "sorry-you-almost-died-in-a-freak-invasion-of-earth" sort of thing. Director Fury had allowed most of the SHIELD agents as much time off as they needed to cope with the hell they had been through. Fiona knew that she'd miss her job sooner rather than later, so she had even signed up to be on call. That way SHIELD wouldn't be completely staff-less if those other-wordly assholes from Norse mythology decided to come back. She picked up her pace as she spotted her hotel. She was already chilled to the bone, but decided it wasn't worth putting up with, and broke into a run. Reaching the posh glass doors, she pulled them open eagerly and relished the warmth that hit her. She stomped her shiny black boots on the mat and shook off her trench coat. Her boots made walking on the slick floors difficult, and she slid several times. When she reached the front desk, she smiled warmly at the woman behind it, only to be greeted with a death stare.

"Um, I have a room for Dagger. Fiona Dagger." Fury always advised the agents use aliases, but Fiona loved her name too much to come up with a different one.

"Room 247. Enjoy your stay." The rickety old woman hardly looked like she meant it. Fiona thanked her anyway and headed towards the lift.

She eventually found her room, slid the card in, and popped open the door. Her luggage was tossed on to a chair, unzipped, and ransacked for pyjamas. Slipping her jeans of, she pulled on old gray sweats and collapsed in to bed. She glanced at the clock on the table and saw it was 4am London time. "Goodnight London. Please be nicer tomorrow."

An hour later, her phone buzzed.

"Hello?" She said groggily in to the receiver.

"Agent Dagger?" came Nick Fury's voice at the other end.

"Speaking. How can I help you?" she replied, fumbling for the bedside light.

"There appears to be some disturbance with gamma radiation near you. We think it may have to do with the tesseract." Nick sounded worried. Scared, even. Fiona blurted the first thing that came to mind.

"How do you know where I am?"

"Ms. Dagger, we are a government agency and you didn't use an alias. It's not hard."

_Oh, crap_ Fiona thought. Fury kept on talking though

"I would normally send Coulsen on these investigations, but you're close, and well…" Nick's voice trailed off, not wanting to think about Phil Coulsen's death. Fiona was quiet for a minute. _I am Phil's replacement?_

"I'll be there. What time?" was all she said.

"10, your time. Call me as soon as you're done. And do you have your badge? We'll send backup to make it more official." Nick Fury reminded her of a mother hen, always fussing over his agents.

"Of course I have my badge. I'm going to get some sleep. Big day tomorrow." She said, flicking off the light and laying back down.

"Goodbye."

Fiona hung up the phone and thought. Had she really been picked to take Coulsen's job, or was it just convenient? He had been her best friend on the job besides Natasha. He had been everybody's friend, but they shared a special bond. They had both believed in The Avengers, before The Avengers had believed in themselves.

"God, that sounds cheesy, but it's true." Fiona rolled over and closed her eyes.

At 8 am London time, her phone buzzed again, this time to remind her to get ready for work.

"Where am I?" she rubbed her eyes "Oh, right. London." It was just as dark and gloomy as the day before. She pushed back the cold hotel sheets and walked over to her case. Searching in vain for a business skirt, she pulled out the next best thing. A blazer, matching trousers, and her favorite deep purple dress shirt was her outfit of choice. Her black hair was straightened, teeth were brushed, and face was washed. Topping it off with mascara and some eyeliner, she finally found her outfit acceptable.

"Showtime!" she posed, looking at herself in the mirror. Assured her gun and tazer were fully concealed, she put on black pumps, slipped her phone and badge in to her pocket, and walked out the door.

**Thanks for reading this! Sorry Sherlock isn't in it yet. Next chapter! If you like Sherlock, please check out my other fanfic. That one is not done yet, but I have 4 or 5 chapters of that up. Hugs and Kittens! **


	2. Chapter 2

**Ch. 2**

A car was waiting for Fiona outside her Hotel. Five men in suits and sunglasses were seated in the large vehicle. _It's like a clown car _she thought as she stepped in to black leather interior.

"Ok men, here's my plan. I walk in and flash my badge around. You guys round up anyone in the building and send them out. I'm pretty sure Col. Fury sent compensation money. It's just one older gentleman who lives in the building, so I think this should take five minutes, tops. Easy-peasey." She had no idea how wrong she was.

When the SHIELD team reached the address at 10 o'clock, they were shocked to see several dozen police cars, along with yellow tape.

"Did anyone tell any of you _anything_ about this?" Fiona asked the men seated behind her.

"Nothing at all Ms. Dagger. We were not informed of this." His placidity towards the situation was inhuman.

"Alright. On the count of 3 get out and look straight ahead. 1… 2… 3!" Fiona swung open the door with the palm of her hand and ducked in to the rain. She walked quickly, with the 5 men behind her, looming like buildings.

"Ma'am! Excuse me! Ma'am! You can't be here!" came a female officer's voice.

"Agent Fiona Dagger, SHIELD." Fiona said as she held up her badge with authority.

"What? There must be some mistake. Nothing is going on here. It's just a murder." The other woman said.

_A murder? This is not sounding good. Fury is going to flip when he hears this _Agent Dagger thought to herself. _And, keep walking fast! You have to look official!_

She pushed through the front door, not even bothering with her badge this time.

"Can I have your attention?" She yelled over the bustle of police. The silence that followed was deafening. "I'm going to ask you all once. Please drop what you are doing and leave immediately."

"What's the meaning of this?" a silver haired man in a sports jacket exclaimed. He had just come out of a side room in which Fiona assumed the murder had taken place.

"Government issues, sir." She said, turning towards him.

"It's not our government! You're American!"

"Thank you for clarifying that. May I ask who you are?"

"I should ask you the same thing. I'm DI Greg Lestrade."

"Fiona Dagger. I'm with SHIELD. Please leave now." Fiona turned around and bumped in to a man wearing the exact same outfit as her, minus the heels.

"I'm sorry, the exit is that way…" She said, eyeing his purple shirt. It looked surprisingly good on him. He had the most mesmerizing eyes, and his raven hair was no different in colour from her own.

"Thank you. I'm not leaving though, just coming in." He said. He had an amazing voice._ Focus Fiona._

"You have to leave. My team is evacuating the building. We are investigating suspicious activity in the area."

"So am I."

"God, you're sexy." Fiona said out loud.

"Thank you. Have a nice day. He brushed past Fiona in to the other room like nothing had happened. The DI followed, along with a blondish man who she had not noticed before. Overpowered by sexy, apparently. Turning to face one of the men on her SHIELD team with a bright red face, Fiona asked "Did I say that out loud?"

"Yes, Ms. Dagger." The agent said, stone-faced as ever.

"Oh. Alright. He still has to leave." She walked in to the murder room, unfazed by the dead man on the floor. She had seen worse.

"Mr. um-"

"Holmes. Sherlock Holmes."

"Mr. Holmes, I'm going to ask you once more to leave, and if you don't, you will be removed forcefully."

"Sherlock, its best if we go. This seems like a big deal, and I think we have learned our lesson on not messing with government agencies." The short blondish man spoke up.

"Fine, John. Lestrade, are you going to clean this up?"

"Don't bother. We are on a very tight schedule." Fiona had no schedule, but it was a good ploy in her eyes.

"There is an unsolved murder in front of you and you want us to leave?" Lestrade was clearly still baffled by it all.

"That's exactly what I want." Fiona said with a smirk.

"Go ahead. But when you're murdered, don't expect us to help you out."

"Why would I need your help? I'd be dead." She asked with a straight face.

"She has a point. Now let's go" the man called John insisted, turning towards the door. The three men left the room, and headed towards the front door. Fiona watched from the doorway. When she was sure they were gone, she turned towards the corpse on the floor. He had been stabbed. It looked strikingly like the way Phil had been killed. That was the last thing she needed, but she knew deep down it was true. Loki was back.


	3. Chapter 3

**Hey guys! Sorry that I haven't been updating lately. Summer break= traveling and stuff. Anyways, Avenge or Die right now, Sherlock's Assistant tomorrow night most likely. Enjoy! :) **

**Ch. 3**

Once the police force had cleared out and it was only Fiona and the other agents in the house, she had the body cleaned up and brought to a morgue. The other agents went along with the corpse to oversee its safe return. It baffled Fiona why they had left her to guard the house with nothing but a gun and a taser, but the majority had left to make sure a dead man was comfortable.

"They're probably scared. Funny how that works." She said to herself as she paced around the living room, watching the front entrance. She continued this for nearly twenty minutes when she heard a thud upstairs. It was dull, like something hitting old wood floors. Then there was a squeak of a window closing. Fiona stiffened and put her hand lightly against her taser. _Oh dear god. No. This is not happening _her mind protested as her feet moved up the stairs. Her high heels were betraying every step, so she slowly pulled them off her already aching feet. Reaching the top step, she slid her taser out of its holster and held it in front of her.

"Hello? Show yourself!" She called down the dusty hallway. A board behind her creaked and Fiona whipped around and fired her taser. A stunned Sherlock Holmes fell backwards, and landed with a crash on the floor.

"Oh my god! I am so sorry! Can you hear me?" Fiona cried as she knelt down next to him.

"Sherlock? Sherlock, are you in here?" came the voice she recognized as John's.

"Oh, um, up here!" she called down the stairs. His footsteps rushed up to the hallway where she knelt, awkwardly poking Sherlock's face.

"What the hell happened?" John's face was a mix of disbelief and worry. He too knelt next to Sherlock and took his pulse.

"I tased him and I think he got knocked out from the fall. Is he ok?" she was still poking his face, trying to wake him up.

"I'm a doctor. He should be fine, but I should probably take him home. Are you the only one here?"

"Yes. Do you need help moving him to your car?"

"Well, about that. We don't have a car. There is a cab waiting outside though." He looked up with a half smile on his face.

"That's the next best thing I guess. Okay, how should we do this?"

"You get his arms, I'll take his legs. Just don't drop him."

Fiona grabbed Sherlock just below his elbows and lifted. John grabbed his ankles and began to walk backwards down the steep stairs. Once they reached the cab, John elbowed the door open and tossed the still unconscious Sherlock in to the back.

"He should be fine. If you want, you can come by and check on him later. Our address is 221b Baker Street."

"I have to admit, I have no idea where that is. If you can't tell, I'm not from around here."

"Of course. There's a Baker Street tube stop. Just get off there. If you're taking the tube that is."

"I will. Thank you." Fiona turned to walk back in to the building. _That was odd _she thought as she climbed the front steps. _Wait a minute! What the hell was Sherlock even doing in here? It's probably not the best idea for me to go and check on him. Could be dangerous._

Two hours later, Fiona was sitting on a crowded subway train wearing a sea green jumper, dark gray jeans and her black boots. Once the train reached Baker Street, she stood up and pushed through the mob of commuters. Yet again it was raining, and the cool London fog caressed Fiona's face and hands. She walked up the street, scanning the house numbers until she found 221. When she rang the doorbell, an older woman answered the doorbell.

"Hello. I'm looking for Sherlock Holmes. Is he in?" Fiona asked as kindly as she could.

"Yes. Right up the stairs, dear." The old woman replied with a smile.

"Thank you." Fiona bounded up the steps and knocked lightly on the door.

"Come in." said a voice behind the door. She turned the knob and walked in to the flat with her arms crossed. Her aim was to be menacing, and try to scare Sherlock in to explaining why he had been at the crime scene. Instead, her jaw just dropped and she stood stuttering in the doorway. Sherlock was seated on the couch with an icepack held to his head. What had surprised her was the fact that he was wearing only a sheet.

"Um, I- I-" she swallowed "Should I go?"

"I just invited you in, did I not?"

"Oh, I guess so."

"Please. Have a seat." He gestured towards an armchair.

"Thank you." She sat down. "Why were you-"

"Why was I at the murder scene after you asked I leave? I can't leave a case unsolved. I suppose your boys have already cleared out the body though."

"Are you some sort of private eye? Did the police hire you or did someone else?"

"Neither. I'm a consulting detective. I solve whatever cases strike my fancy. Which is most of them."

"A consulting detective? Did you make that up?"

"Yes."

"Ok then. What were you doing when you snuck back in?"

"I was sneaking back in."

"Of course you were. _Why _were you sneaking back in?"

"I've already told you. I can't leave a case unsolved. Your questions are very round-about. And rather stupid."

"Mr. Holmes, this is a very serious matter. I ask you treat it as such."

"Are government officials taught to speak that way? You sound just like my brother."

Fiona sighed and rolled her eyes.

"I'll will be back tomorrow with further questions. We may need to take you in to custody if you have found out any classified information. Until then, Mr. Holmes." She stood up and walked towards the door. Walking back in to the fresh fog, she pulled out her phone.

"Put Natasha Romanov on the line. I need to vent."


	4. Chapter 4

**Hello! Here is chapter 4 of Avenge or Die! Here come the avengers! Yay! I'm using too many exclamation points! I'm going to stop now!**

**Ch 4**

"… and then he just shows up at the crime scene! He climbed in the window, Tasha! Yes, the window. I mean, why in hell would you sneak in to a crime scene? I'm just baffled!" Fiona stormed down the street, phone in hand, and her boots slapping against the rainy sidewalk.

"Don't you think you're overreacting? Maybe Scotland Yard should be helping. It seems right, considering it's their country at risk." Natasha Romanov's voice crackled through the phone.

"That's the thing. He doesn't work for Scotland Yard! He's a 'consulting detective'. He made that up, you know."

"Ok. Fiona, just calm down and take a deep breath."

Fiona slowed down a bit and relaxed her grip on the phone. After breathing in and out several times, she spoke again.

"Alright, I'm better now. I'll continue on a more civilized level. Do you know if they're sending anyone out here to do any tests?"

"I think Banner is leaving tonight, and Rodgers might go with him. He hasn't been to London in seventy-something years, so that should be good for him."

"What about Thor? Have we managed to get in contact with Asgard?" Fiona lowered her voice as a group of pedestrians passed.

"There's no sign of any more disturbances, but he could be on Loki's tail already. You never know with gods."

"That's true. I have to go, but I'll talk to you later. Can you have Fury send you here? I'm going insane."

"I'll try, but I can't promise much. They have a ton of agents who are still on vacation, so it's been really busy around here."

"Alright, I'm going sightseeing for an hour or two. Bye."

"Talk to you later." Fiona hung up the phone and stuck it in her back pocket. This was defiantly the most interesting holiday she had ever been on.

o0O0o

Fiona was a proper tourist for the next hour and a half. She posed in front of Big Ben and asked a passerby to take her picture. Next she stood outside Buckingham palace, gaping at the structure and snapping more photos than she could count. It wasn't that she needed the pictures or the souvenirs, but she needed to focus before she was thrown head first in to a case. She had been planning on a relaxing, if not dull, vacation, and although her work suited her better, she had to snap out of civilian mode.

She took the tube to her hotel, and upon reaching the door of her room, stopped dead in her tracks. Her luggage was gone, the beds were stripped clean, and the blinds were drawn shut. Fiona sighed and rubbed her temples, fighting the urge to scream. Biting her lip, she sat on the bare bed, before realizing it _wasn't_ bare. A crisp white envelope with the SHIELD logo across the front was to her right, in between where the two pillows had been. Fiona dragged it towards herself half-heartedly, and tore it open. A scrap of paper fluttered out, with one word scrawled in cursive.

_Embassy_

Fiona silently cursed Nick Fury. She stood up, planning to walk in to the US Embassy and confront him. A SHIELD agent could quit, or be dishonorably discharged from service, but in fear of blackmail on the agency's part, they could not be fired. She walked calmly out of the room, patting her pockets to see everything was there, but inside, she was boiling. Over and over, her speech ran through her head, running circles, jumping and trampling other smaller thoughts. She didn't even really know where the embassy was, but she was too mad to care.

Fiona found the embassy within the hour. After showing her at the front desk, she was shown in to a closet, that was in fact, an elevator. An extremely large bald man with an earpiece and a suit stepped in with her. He slid a cardboard box over, pulled a panel on the floor open, and stepped on a red button that had been hidden. Fiona felt her stomach drop as the elevator groaned and moved downward at a slightly sickening pace. This went on for nearly a minute, with the bald man standing unmoving in the corner, and Fiona drumming her fingers on a handrail. She was grazing through her speech one last time when the grating noise stopped and the door open. Stepping out, she noticed Fury with his back turned, having a very animated conversation with someone. She walked over and tapped him on the shoulder. But he spoke first.

"Agent Dagger. I would like to introduce you to Mr. Sherlock Holmes and Dr. John Watson. But I've you've already met."

Sherlock grinned slyly and wiggled his fingers at her in mock greeting. John cleared his throat and mouthed _sorry_ at her.

"You- you're the guy from…" she turned to Fury "You're kidding right? Why the hell is he here?"

"Mr. Holmes has offered to help us track down Loki. Although he is entirely skeptical that we are searching for a Norse god, he's still the best man for the job. "

"Sherlock, please." He said, rocking back and forth on the balls of his feet.

"You'll be assisting Sherlock in his search. Whatever he needs as far as equipment, you will provide. You'll also be helping Romanov with keeping the media silent."

"I have to work with this clown!? What are his qualifications?"

"Oh no." John muttered.

"Well, I know that you're 26 years old, living alone in a condo in Washington D.C. You have a brown and white terrier that you've left with your older sister for your trip to London. Your favorite color is purple, you have naturally _curly_ hair, even though it is straightened within an inch of its life at present, and you paint in your little spare time. You also have anger management issues. They are not_ that _prominent, but you did tase me."

"How on earth did you know that?" Fiona asked, with her jaw hanging.

"I'm highly qualified."


End file.
